Fire resistant hydraulic fluids are widely used in mining operations and these fluids are usually water-in-oil emulsions. Conventionally the hydraulic fluid emulsion is made up by the oil supplied and then shipped to the mine site. Since the fluids are typically 40% water almost half of the shipping costs are for shipping water. Preparation of the emulsion at the mine site would avoid this but this has not been widely practiced heretofore because the emulsification equipment conventionally used is both sophisticated and expensive and, of course, individual emulsification equipment would be needed at each site. If a cheap, simple emulsification process were available the foregoing problems could be eliminated.